I agree, it would work just fine! I plan on using the nn Bella for Isabelle, which isn't really that different from Ariel nn Ella. I don't think you really need to go for Ariella or Arielle to make Ella more obvious, but I personally would, just because I like that they're more feminine and frilly. I think Ariella nn Ella would be pretty adorable, but if you like Ariel nn Ella more, I don't see any reason why you couldn't use it. I don't think it's that hard to get to Ella from Ariel.

In my opinion Ella is a perfect nn for Ariel. Ariel is the kind of name when you and your child have a certain freedom of choosing a nickname. She might be nicknamed Ari, Ella or Elle. I wouldn't even doubt it.

I don't think so. I think it could work. Heck, I am still tempted to use Ella as a nn for Evangelina, so do what you want!

pet peeves: nicknames as given names; unconventional spellings; masculine names on girlsnot-so-guilty pleasures: five-syllable girls' names; virtue and nature names; over-the-top antique names for boys
(if i repeat name suggestions in a thread, it's because i like them! no apologies here for repeats of great names! )